[ivwshane]

I've got a mobo with about four-six capacitors that are the same size that need to be replaced.

The soldering part looks pretty easy, only two solder point per capacitor and they are all located in an open area on the mobo.

The question I have is how do I determine what kind of capacitors I need to replace them with.

Are there markings on the capacitor that I should be looking for?


And would anyone know off hand a rough idea of the cost of a capacitor?

[msgwtco]

first look rating in uF or mfd (microfarads) replace the board capacitors with ones of value equal to this

Next check the voltage rating on them. Voltage rating indicates the maximum voltage the capacitors are meant to handle. Make sure you get equal or greater values on these.

Finally, when you are soldering them in note the polarity. the Cathode (negative side) is always noted with a - (minus sign).

Capacitors are usually relatively inexpensive. a few dollars i think.

[ivwshane]

Would there be any advantage to buying ones with a higher voltage rating?

Thanks for the info!

[Tacdriver]

Originally Posted by ivwshane

Would there be any advantage to buying ones with a higher voltage rating?

Thanks for the info!

No No No!!!! Always replace the caps with the same ones. Make sure the polarity is correct and always use a low temp solder sucker or solder wick when removing the solder. Why are you replacing them? Are they starting to expand at the top?

The caps would typically cost between .50 to $2.00 at the most.

[basketofkittens]

A couple of minutes on google got me this:
http://www.badcaps.net/

Maybe there's something on there for you.

[ivwshane]

I checked there and he seems to charge quite a bit plus the mobo in question wasn't listed.

The reason I'm doing this is just for fun and for the learning experience. I just aquired an old pc and the capacitors are blown (expanded) and a couple of them seems to have leaked.

It looks easy enough and I've read about several people that have done it.

Anyone know of a good reliable and cheap place to buy these? I'm sure radio shack has them buy they tend to overcharge on these kind of parts.

[basketofkittens]

Any electronics component reseller will do you fine. Digikey is good, so is Mouser.

[Chair]

yeah I've replaced motherboard caps before... pretty simple work, motherboard worked better than ever afterwards (old slotA board) and still works to this day (replaced them a couple years ago)

[msgwtco]

the voltage rating on the capacitors are just an indicator of how much voltage the capacitors can handle before they do not work properly anymore.

it is safe to have a higher voltage rated capacitor than the orignal. Example if your board cap is rated at max 16V you can surely use a max 20V rated in it's place. there is no real advantage to doing this though. Just make sure the capacitors you buy have an equal or grater voltage value cap in its place.

http://www.bcae1.com/capacitr.htm

Over Voltage:
All capacitors have a voltage rating. This tells you how much voltage the dielectric (insulator) can withstand before allowing DC to pass between its plates. Sometimes a capacitor has a working voltage (i.e. WVDC working voltage DC) and a surge voltage. The working voltage tells you how much voltage the capacitor can withstand long term (for the normal life of the capacitor). The surge voltage is the voltage is can withstand for short periods of time. Generally, if too much voltage is applied to a capacitor, it will fail. In electrolytic capacitors, the forming voltage (voltage used to anodize the plates) and the thickness of the paper element determine the working voltage of the cap. In film type capacitors, the insulating material (polyethylene, polypropylene...) will determine the maximum working voltage.

But be sure you get the exact correct rating in microfarads (mfd or uF) and you note correct polarity. if you install a capacitor backwards it can explode.

[ivwshane]

Ok so I ordered the parts from digikey and can I say I hate companies that don't show their true shipping charge

Not only did they charge me over $5 for shipping (I ordered six capacitors) but then they also charge over $5 for handling!

Very annoying!

[basketofkittens]

Originally Posted by ivwshane

Ok so I ordered the parts from digikey and can I say I hate companies that don't show their true shipping charge

Not only did they charge me over $5 for shipping (I ordered six capacitors) but then they also charge over $5 for handling!

Very annoying!

Yeah, but how else are they going to make a profit selling six capacitors? Their main business if obviously selling large amounts of components.

[ivwshane]

Come on! a handling charge? WTF is that!

They better come in some nice packaging

[ivwshane]

So I've replaced the capacitors and the system now boots and seems fairly stable

Soldering the connectors was actually harder than it looked, it was hard to get solder to connect to the socket whole.

[funkgab]

great job yeah soldering is a pain in the ass =/

[thadood]

Gj, I would have said fuck it and bought a new board.

[ivwshane]

I got the board free so I had nothing to lose. Now if one of my important systems has a similar issue (or any electronics device for that matter) I know I can fix it myself.